Adamantane polyesters

ABSTRACT

LINEAR POLYESTERS HAVING GOOD TEMPERATURE, HYDROLYTIC AND U.V. STABILITY ARE PREPARED FROM HYDROCARBON ADAMANTANE DIOLS AND CYCLOALKYL ORGANIC DIACIDS. THE HYDROXYL GROUPS ARE BRIDGEHEAD POSITIONS IN THE ADAMANTANE MOIETY AND PREFERABLY THE ADAMANTANE MOIETY CONTAINES SUBSTITUENTS AT THE REMAINING BRIDGEHEAD POSITIONS THUS REMOVING ALL TERTIARY HYDROGEN-ATOMS THEREFROM. THE POLYESTERS ARE USEFUL FOR PREPARING COATINGS, FILMS AND FIBERS.

United States Patent U.S. Cl. 260-75 R 6 Claims ABSTRACT OF THEDISCLOSURE Linear polyesters having good temperature, hydrolytic andU.V. stability are prepared from hydrocarbon adamantane diols andcycloalkyl organic diacids. The bydroXyl groups are bridgehead positionsin the adamantane moiety and preferably the adamantane moiety containssubstituents at the remaining bridgehead positions thus removing alltertiary hydrogen-atoms therefrom. The polyesters are useful forpreparing coatings, films and fibers.

This application is a continuation-in-part of application Ser. No.586,825 filed Oct. 14, 1967 now US. Pat. 3,467,627.

BACKGROUND Adamant'ane (tricyclo-[3.3.1.1 ]decane) has :a carbonstructure containing ten carbon atoms arranged in a completelysymmetrical, strainless manner, wherein four of the carbon atoms are inbridgehead positions in the rings. The typographical structure ofadamantane is often represented as:

There are four tertiary hydrogen atoms, one at each bridgehead carbonatom. All four bridgehead carbon atoms are equivalent to each other andlikewise all rings are equivalent.

The preparation and use of monoesters of l-adamantane carboxylic acid istaught in the prior art by Spengler et al., Erdol undKohle-Erdgas-Petrochemie, vol. 15, pp. 702-707 (September 1962).

The preparation and use of monoesters of adamantane- 1-01 is taught inUS. Pat. 3,081,337.

The preparation and use of diesters containing an adamantanenucleus isshown in US. 3,398,165 of Irl N. Duling and Abraham Schneider, issuedAug. 20, 1968.

A polyester produced from the dimethyl ester of 1,3- adamantane diacidand 1,4-bicyclo(2.2.2) octane dimethanol is shown in French Pat.1,374,693.

DESCRIPTION OF THE INVENTION The present invention relates to linearpolyesters produced from the substituted adamantane diols saidpolyesters having superior properties in regard to stability at hightemperatures, hydrolytic stability and ultraviolet stability over linearpolyesters produced from adamantane diacide.

The novel linear polyesters of the present invention are comprised of asubstituted adamantane diol wherein the substituent is a hydrocarbonradical and an organic diacid component. The polymers may be describedas linear polyesters comprising a substituted adamantane diol having thestructure H OH where R is a radical having 0 to 20 carbon atoms selectedfrom the group consisting of hydrogen and hydrocarbyl and R" is ahydrocarbyl radical having 1 to 20 carbon atoms and an organic diacidcomponent selected from the group consisting of a diacid having thestructure ll HO-CR( iOH and a mixture of diacids having the structureH0iiRii0H where R is a bivalent organic radical.

The preferable polyesters according to the present invention comprise ahydrocarbon substituted adamantane diol having the structure HO OH whereR is a radical having 0 to 20 carbon atoms selected from the groupconsisting of hydrogen, alkyl, cycloalkyl and aryl and R" is a radicalhaving 1 to 2-0 carbon atoms selected from the group consisting ofalkyl, cycloalkyl and aryl and an organic diacid component selected fromthe group consisting of a diacid having the structure H0-iiRii-OH and amixture of diacids having the structure 0 HO- -R( iOH where R is abivalent organic radical. A preferred R is a cycloalkylene radicalhaving 4 to 12 carbon atoms.

The term hydrocarbyl is used to designate a hydrocarbon radical whichcan be from the group alkyl, cycloalkyl, aryl, alkaryl, aralkyl,alkcycloalkyl, cycloalkalkyl, cycloalkaryl, arcycloal'kyl and anycombination of hydrocarbon radicals. Some examples of the above radicalsare methyl-, cyclohexyl, phenyl-, benzyl-, tolyl-, methyl-hexyl-,heXyl-ethyl-, cyclopropyl-phenyl-, phenyl-cyclohexyl-, and the like. Theabove hydrocarbyl radicals are attached at either the 1 or 3 positionsor both on the adamantane molecule.

The adamantane starting material used to produce the polyesters of thepresent invention is a bridgehead monoor di-alkylated or arylatedadamantane having the general formula where R and R" have thesignificance previously given. The alkylor cycloalkyladamantanecompounds can The substituted adamantanes for the present invention canhave either non-branched or branched al-kyl groups and can have one ormore cycloalkyl or aryl radicals in the substituted adamantane moietywith a total number of carbon atoms in each R group ranging up to 20.The diols of the alkylated adamantanes can be produced by reacting theparent hydrocarbon with chromic acid according to the proceduredisclosed in US 3,383,424, Robert E. Moore, issued May 14, 1968. Thisprocedure Will also produce the diols of the arylated adamantanes.

Examples of such reactants are the 5,7-dihydroxy derivatives of thefollowing hydrocarbons: l-methyladamantane; or l-ethyladamantane;1,3-dimethyladamantane; 1- methyl-3-ethyladamantane;1,3-diethyladamantane; l-npropyl or l-isopropyladamantane;l-n-butyladamantane; 1,3-di-n-pentyladamantane;l-methyl-3-heptyladamantane; l-n-decyladamantane;1-n-decyl-3-ethyladamantane; 1- methyl-3-propyladamantane;l-isohexyladamantane; 1- methyl-3-cyclohexyladamantane;l-phenyladamantane; 1- methyl-3-phenyladamantane; 1,3-phenyladamantaneand the like.

In regard to the structures given above, it should be noted that of thesubstituents specified at the bridgehead positions of the adamantanemoiety only R may be a hydrogen atom. Thus, in any composition accordingto the invention, there will at most be only one tertiary hydrogen atomin each adamantane moiety. Preferred compositions have notertiaryhydrogen atom in the adamantane moiety, thus in preferred compositions Rwill be either an alkyl, cycloalkyl or aryl group. More preferablybecause of. the ease with which they may be obtained, the bridgeheadsubstituents will be methyl or ethyl groups or both.

The linear polyesters are produced by the condensation of substitutedadamantane diol as described above with an organic diacid or a' mixtureof organic diacids, esters or halide thereof depending on the method ofpreparation.

The organic diacid is characterized by the formula O no-ii-n-t'i-onwherein R, the bivalent radical can be selected from the followinggroups: aromatic, aliphatic, cycloaliphatic, combination of aromatic andaliphatic, heterocyclic, bridged organic radicals wherein the bridge isoxygen, nitrogen or sulfur and substituted groups thereof. Suchsubstituents include halogen, amino, methoxy, sulfide and the likeprovided that such substituents do not interfere with thepolyesterification. The preferred R group is a radical having 1 to 20carbon atoms selected from the group consisting of alkylene,cycloalkylene and arylene. No ethylenic unsaturation is present in the Rradical.

In carrying out the esterifications, the diacids 0 0 H II HOCR-COH willusually be employed in the diester or diacyl form as pointed out below.The organic diacid can be, for example, the acid form, the dimethyl anddiethyl esters, the dioyl chlorides or the anhydrides of the followingacids: adipic; pimelic; suberic; azelaic; sebacic; undecanedioic;dodecanedioic; malonic; succinic; glutaric; cyclopentane dicarboxylic;cyclohexane dicarboxylic; Decalin dicarboxylic; orthophthalic;isophthalic; terephthalic; 1,2,2-trimethyl 1,3 cyclopentanedicarboxylic; bromopropanedioic; 3-methyl-1,l-butanedicarboxylic;mesoxalic; 4,6-dimethylisophthalic; l-glutamic; 2,6-naphthalenedicarboxylic; 0,0'-azobenzenedicarboxylic; p,p'-azobenzene-dicarboxylic;o,o-azoxydibenzoic; p,p-benzophenone dicarboylic;2,3-dihydroterephthalic; 1,3,3-dithiobis(2-aminopropanoic);2,5-furandicarboxylic; oxydiethanoic; 3,5- pyridinedicarboxylic;a-l-toluenedicarboxylic; tetrachloro phthalic; quinolinic;u-amino-succinic; tartronic; benzyltartronic; 2,3-thiophenedicarboxylic;isohemipinic and the like.

The selection of a particular diacid component and the mole ratio to beemployed will depend on the desired properties of the final polyester.

The mixture of diacids can for example be a mixture of an aliphatic, acycloaliphatic and an aromatic diacid; it can be a mixture of acidswithin one class such as adipic and sebacic or a mixture of diacids fromtwo or more classes such as adipic, sebacic and terephthalic acids.

Any proportion of mixed acids may be employed. For example, the acidreactant can contain 1% (mole) of an aromatic diacid and 99% (mole) ofan aliphatic diacid.

A particularly preferred acid would be a cyclic acid having 6 to 14carbon atoms such as cyclopentane dicarbox-ylic acid, Decalindicarboxylic acid and the like.

Polyesters produced from aliphatic diacids were found to be amorphous(essentially non-crystalline). Both annealing and precipitation fromsolution were tried on several samples Without developing anycrystallinity detectable by X-ray analysis.

The aromatic polyesters do not show a tendency to crystallize from meltpolymerization; however, in solution polymerization and in precipitationfrom solvents during the workup of the polyesters, they crystallizefairly readily on the order of about 30% as determined by X-ray scan.

In carrying out the esterifications, stoichiometric proportions of thereactant can be used. Generally a molar ratio of acid reactant to thedihydroxy alkyladamantane reactant in the range of 0.95: 1.0 to 1.0:1.10 will be used in carrying out the reactions.

The linear polyesters according to the present invention have aninherent viscosity in the range of .05

Where 7relative =5) t =flow time through a viscometer of a liquidreference.

t=fiow time through the same viscometer of a dilute solution of polymerin the reference liquid.

C=concentration of polymer in solution expressed in grams/decliliter.

The solvent employed was 60% phenol, 40% tetrachloroethylene.Concentration was 50:.05 grams per/d1. Where the polymer was soluble inbenzene the number average molecular weight (ll I was measured directlyin a Mechrolab Osmometer. It is, however, difficult to measure theaverage molecular weight of all of the polyesters particularly thosecontaining an aromatic nucleus because of their limited solubility insuitable solvents. For this reason, the inherent viscosity was employedto characterize these polymers. The inherent viscosity is indicative ofthe degree of polymerization and is used herein as measure thereof. Byanalogy with the known inherent viscosity and weight average molecularweight (M relationship of Dacron it is possible to estimate from theinherent viscosities of the instant polyesters that the number averagemolecular weight of the linear polyesters of the present invention is inthe range of 900 to 60,000

Where E was determined directly and also determined by analogy frominherent viscosity in regard to Dacron it was found that the valuesagreed with for the lower values and 1-20% for the high values which iswithin the estimated accuracy of the Mechrolab Osmometer. This agreementof estimated and measured molecular weight is considered valid for thepolyester produced from the aliphatic acids, however, no attempt hasbeen made to relate the inherent viscosity to molecular weight for thepolyesters produced from aromatic diacids.

The linear polyesters of the present invention, depending on theirdegree of polymerization are viscous liquids to solids. Thosecompositions which are viscous liquids have particular utility aslubricants or as components in lubricating and grease compositionsbecause of their stability. The liquid polyesters can also be used asplasticizers for solid polymers of the present invention, wherein theyhave excellent compatibility and as plasticizers generally for polymericmaterials. The solid polyesters of the type described above may be usedto produce films.

The films produced by the condensation of alkyladamantane diols andaliphatic acids are non-crystalline and essentially amorphous, thus haveutility as coating for paper in order to produce moisture-imperviousbarriers or as strippable coatings, for example as a protective coatingfor metal parts prior to use.

Where the acid portion of the polyesters if 70 to 100% aromatic,aromatic, the polymers have a high degree of crystallinity and aresuitable for producing films and fibers.

It is possible to increase the length of the linear polyester chains byusing a suitable coupling agent, for example, toluene diisocyanate. Thecoupling can take place at either the terminal alcohol or acid sites onthe polyesters. The mechanism of the coupling at the acid site for theisocyanate can be represented by:

The mechanism of the coupling at the alcohol site for the isocyanate canbe represented by:

where A is the adamantane nucleus and R is as previously indicated.Other suitable coupling agents include diacyl chlorides, glycols,diamines and the like. The selection of the proper coupling agent ismade on the basis of the terminal polyester groups which can bedetermined from the original stoichiometry. The resulting coupled linearpolyesters are linear and have essentially the same properties as linearpolyesters having corresponding polymer chain length. The coupled linearpolyesters have inherent viscosities in the range of .20 to 2.0.

Normally coupling would be employed in the case of short chainpolyesters in order to increase the apparent degree of polymerizationfor these polyesters without substantial change in the polyesterproperties.

The polyesters of the present invention have high stability againstthermal and oxidative degradation and good hydrolytic stability. Thepolyesters of the present invention are the reverse of the polyesterdescribed in the prior art referred to above. In other words, theadamantane nucleus (A) is attached to an oxygen atom of the carboxylicgroup in this fashion,

rather than to the carbon atom in the following linkage,

i AC0 The present structural arrangement,

i AOC resulting from the adamantane derived reactant being an alcoholinstead of an acid, imparts greater stability to the polyester productof the invention as compared to that shown in the prior art.

A well-known decomposition route for conventional types of estersdepends upon their ability, under appropriate conditions, to transfer ahydrogen atom from the beta position of the alcohol derived moiety inthe following manner:

This decomposition results as shown in the conversion of the ester intoan acid and an olefin. The present esters cannot undergo thisdecomposition as this would require the formation of a double bond inthe adamantane nucleus which will not occur. The decomposition cannotoccur because the carbon atom in the adamantane nucleus through whichthe ester bond is made is a quaternary carbon atom.

Another reason for the overall better stability of the presentpolyesters as compared to the prior art polyesters made from1,3-adamantane dicarboxylic acid is the fact that the present polyestershave at most only one tertiary hydrogen atom attached at each adamantanemoiety and preferably have no tertiary hydrogen atoms. In comparison, apolyester of the prior art has two bridgehead tertiary hydrogen sites oneach adamantane moiety. These are active sites constituting spots in themolecule where oxidation and peroxide formation can occur.

Another reason for the superior stability of the present polyesters isthat the ester structure represented by will be less likely to undergohydrolysis under nonacidic conditions than the reverse structure This isan important property for the polyester since they may be expected tocome into contact with water when utilized as described.

Preparation of linear polyesters using the bridgehead alkyladamantanediols is not as readily accomplished as when aliphatic glyocls areemployed. Attachment of the hydroxyl group at the bridgehead carbon ofthe adamantane nucleus makes the group relatively inactive. Hence, manyof the known methods of producing polyesters may not be suitable formaking the products of the present invention. For example, conventionalcopolymerization of the 1,3-diol with an aromatic diacid by means of anacidic catalyst generally is not a suitable way of preparing thepolyester.

Several suitable procedures, however, have been found. These includetransesterification, melt polymerization using anhydrides, meltpolymerization using acyl chlorides, inert solution polymerization andpyridine solution polymerization. These procedures will be set forth indetail in the examples.

The crude reaction product can be worked up in the usual manner forpolyesters. For example, the crude polyester can be dissolved in asolvent such as benzene or toluene and precipitated by addition to coldmethanol. This procedure can be repeated four or five times to obtain apure product.

The example presented herein are intended to be merely illustrative andare not intended to limit the scope of the claims. Certain ratios ofreactants have been specified. It is to be understood that those ofskill in the art will be able to select the respective proportion fromeach range so as to produce compositions within the spirit and scope ofthe invention as disclosed. The examples provide guidelines to indicateto those of skill in the art the means and manner of reactant selection,procedures for utilizing the reactants, and the general nature of thepolyesters to be obtained.

POLYESTERS PRODUCED FROM ALIPHATIC DIACIDS MELT TRANSESTERIFICATIONExample I 1,3-dihydroxy-5,7-dimethyladamantane (3.00 g.=.0153 moles)diethylmalonate (2.45 g.=.0153 moles) and tetraisopropyltitanate (.25ml.) were placed in a polymerization tube at room temperature. A slowstream of nitrogen was bubbled through the mixture as the temperaturewas raised to 195 C. over a period of one hour. The theoretiwere mixedand heated cautiously. Evolution of HCl was fairly rapid as the mixturewas gradually heated to 150 C. for 2 /2 hours. A yellow-brown colordeveloped. Traces of HCl evolution could still be detected over theviscous melt. Cooling to room temperature gave a very viscous liquidpolyester (m =.08; tg= 12 C.).

SOLUTION POLYMERIZATION USING ACYL V CHLORIDES Example IV Adipoylchloride (2.80 g.=.0153 mole), 1,3-dihydroxy- 5,7-dimethyladamantane(3.99 g.=.0l53 mole), and 70 ml. benzene were placed in a 100 ml. roundbottom flask equipped with a reflux condenser and stirrer. The mixturewas refluxed 43.5 hours and the solvent removed by freeze-drying. Theproduct was a very viscous oil. The infrared spectrum was as expectedfor the polyester. The number average molecular weight was 1415(Mechrolab Osmometer) and the inherent viscosity was .11.

The various polymerization reactions set out above were performed forvarious aliphatic diacid derivatives using approximately the same molarrelationships. The results of these runs and of some of the examplesabove are set out in Table I.

TABLE I m. mmdL/g. MN X10 v 10 C.

Malonate: Melt transesterification/diester 09 1, 620 618 1, 100 99Glutarate:

Melt/anhydride 4, $362 226 5, 000 200 51 Melt transesterificationdicster Melt/anhydride l 16 2, 820 355 2, 600 385 Melt/diester 10 l, 30028 pate:

M It ac 1 chloride 08+ 9 5+ 1. 08- 12 e {)0}, 17 ii "96; 31; 1 8? g S lt a l l-l 'de l 5 -3' o 63? i f. l 19 3, 660 274 3, 350 298 24 10 1, 250800 1', 300 769 18. 2 12 1, 700 688 42. 5 Do 09 2 1, 480 675 1, 100 90820. 6

l\ Iv=number average molecular weight calculated from the equation mfiwlz where ITw is the weight average molecular weight as determinedfrom inherent viscosity.

2 Probably high due to some insolubles in sample.

cal amount of ethanol (1.8 ml.) was collected within three hours. Themixture was heated an additional six hours under vacuum ,(.25 mm. Hg) at195 C. and one and one-half hours at 220 C. The viscous brown mixturewas allowed to cool. A brittle clear polymer resulted. This was groundto a powder. It melted to a yellow oil at 73-82. When dissolved inbenzene-acetone mixtures and the solution partially evaporated, a solidwas obtained which did not melt at 310 C. The number average molecularweight (Mechrolab Osmometer) was 1616 and the glass transition (by DTA)occurred at 99 C. By I.R. the polyester was seen to be predominantlyhydroxyl terminated.

MELT POLYMERIZATION USING ANHYDRIDE Example II 1,3 dihydroxy 5,7dimethyladamantane (3.0 g.= .0153 moles), glutaric anhydride (1.74-g.=.0153 moles), and a trace of p-toluene sulfonic acid were placed ina polymerization tube and heated to 190 C. under nitrogen. After fourhours, a vacuum was pulled on the system. The temperature was increasedto 250 C. and the reaction run 25 hours. The melt was brown andappreciably viscous. The polyesters set to a glass on cooling (tg=5l0 C.by DTA; m =.25; llI =4430, Mechrolab Osmometer in benzene solution).

MELT POLYMERIZATION USING ACYL CHLORIDES Example III 1,3 dihydroxy 5,7dimethyladamantane (8.43 g.== .043 mole) and adipyl chloride (7.86g.=.043 mole) POLYESTERS PRODUCED FROM AROMATIC DIACIDS Melttransesterification Example V 5.00 grams (.0255 mole) of1,3-dihydroxy-5,7-dimethyladamantane, 4.94 grams .0255 mole) ofdimethylterephthalate and .40 ml. of tetraisopropyltitanate catalystwere placedin a polymerization tube under a slow stream of nitrogen. Thetube was immersed in a heating block maintained at 195200 C. The meltwas colorless. After approximately one hour, methanol started collectingin the cold receiver. After 2 hours about 50% of the theoretical amountof methanol had been collected. The temperature was increased to 250 C.After four additional home about of the theoretical amount of methanolhad been collected and a vacuum was slowly pulled on the system. A fullvacuum (less than .2 mm. Hg) was maintained for approximately four hoursduring which time the material became a non-flowing foam. Thepolymerization tube was cooled and broken to remove the solid polymer.After grinding, a brown powder having an inherent viscosity of .09 wasobtained. Differential thermal analysis (TDA) showed a transition at192-225 C. X-ray analysis showed about 30% crystallization afterprecipitation from benzene solution. The infrared spectrum was asexpected for the polyester.

INERT SOLUTION POLMERIZATION Example VI1,3-dihydroxy-5,7-dimethyladamantane (3.00 g.=.0l53 moles) andterephthaloyl chloride (recrystallized from n-hexane; melting point81.8-82.6; 3.10 g.=.0153 moles) were refluxed with 50 ml. benzene undera nitrogen atmosphere. An infrared spectrum after 7 hours refluxingshowed that little reaction had occurred. After 4 more hours ofrefluxing an aliquot spectrum showed a somewhat stronger ester bandrelative to the acyl halide band. The benzene was displaced by p-xyleneto allow a higher reflux temperature (138 C.). After 186 hours ofreflux, the polymer was isolated by redissolving in benzene and pouringthe solution into methanol to reprecipitate it. The isolated yield was3.8 g. (76% of theoretical). The polyester was estimated to be about 30%crystalline by X-ray analysis. DTA showed an apparent glass transitionat about 165 C. =.09; MN=1490).

PYRIDINE SOLUTION POLYMERIZATION Example VII 1,3dihydroxy-5,7-dimethyladamantane (5.88 g.=.030 moles), terephthaloylchloride (6.09 g.=.030 moles), and reagent pyridine (250 ml.) werestirred in a 500 ml. flask under a nitrogen atmosphere. A yellow-orangecolor immediately developed and the solution became warm. The solutionwas refluxed 6 hours, allowed to stand at room temperature for 64 hours,then refluxed for a further 48 hours. A deep orange color developedduring this time. The solution was poured into methanol and the polymerpowder filtered out and dried (n =.l).

POLYMERIZATIONS USING MIXED DIACIDS MELT TRANSESTERIFICATIO'N ExampleVIII 1,3-dihydroxy-5,7-dimethyladamantane (4.70 g.=.024 moles),dimethylterephthalate (3.20 g.=.0164 moles), dimethyladipate (.95g.=.00547 moles), and a few drops of tetraisopropyltitanate catalystwere placed in a polymerization tube under a slow stream of nitrogen.The tube was immersed in a heating block maintained 'at 195200 C. Themelt was colorless. After approximately one hour, methanol startedcollecting in the cold receiver. After 18 hours, about 80% of thetheoretical amount of methanol had been collected. The temperature wasincreased to 250 C. After 4 additional hours, about 90% of thetheoretical amount of methanol had been collected and a vacuum wasslowly pulled on the system. A full vacuum (less than .1 mm. Hg) wasmaintained for approximately 12 hours, during which time the materialbecame a non-flowing foam (at 250 C.). The polymerization tube wascooled and broken to remove the solid copolymer. After grinding, anorange powder having an inherent viscosity of 0.11 was obtained.Differential thermal analysis (DTA) showed a glass transition at 150160C. The infrared spectrum was as expected for the interpolyester.

COUPLING Example IX 2.00 g. of the interpolyester of Example VIII wasdissolved in benzene and small portions of solution of toluenediisocyanate in benzene added to the refluxing solution over a period ofthree hours. By the end of this time a fairly large (50%) excess ofisocyanate had been added. A small amount of gel which formed onstanding overnight was removed by filtration. The copolymer was isolatedby pouring the solution slowly into a stirred excess of methanol. Theorange powder was filtered otf and dried under vacuum to give 1.2773 g.(64%) of the recovered copolymer. The inherent viscosity of this polymerwas 0.21.

FILM CASTING Example X Benzene solutions of the polyester prepared inExamples V and VI (ca. 20% solids) were cast mil thickness) on glassplates using a doctor blade. Most of the benzene was removed by a streamof air across the film at room temperature. The films were then heatedto C. and a vacuum applied for one hour. The resulting films werebrittle but were clear and transparent.

POLYESTER FROM CYCLIC DIACID MELT POLYMERIZATION USING ANHYDRIDE ExampleXI l,3-dihydroxy-S,7-dimethyladamantane (19.63 g.=0.1 mo e),1,2-cyclohexane dicarboxylic anhydride (15.42 g.=0.1 mole), andp-toluene sulfonic acid (0.2 g.) were heated in a polymer tube for twohours at 180 C., then two hours at 225 C. Nitrogen was introduced underthe liquid surface via a capillary to provide stirring and an inertatmosphere. A portion (about six inches) of the polymer tube was abovethe heating zone to act as a reflux condenser. Occasionally, it wasbriefly immersed in the heating zone to melt the collected condensedsolids back into the main melt. The melt viscosity increased appreciablyduring this time. The temperature was raised to 250 C. and a vacuum 0.2mm. Hg) was maintained for an additional two hours. The melt was allowedto cool overnight, the tube broken, and the polymer recovered. Thepolymer was a clear, glassy material with a slight yellow cast. It hadan inherent viscosity (0.5% in 60% phenol-40% tetrachloroethylene at37.8 C.) of 0.32 dl./ gm. and a glass transition (by differentialscannig calorimetry) around C.

The invention claimed is:

1. A linear coating, film and fiber forming polyester characterized ashaving a diol component and a dibasic component consisting essentiallythe following structural unit where R and R are radicals having 1 to 20carbon atoms selected from the groups consisting of alkyl, cycloalkyland aryl and R is a bivalent cycloalkylene radical having 4 to 12 carbonatoms, provided the ratio of diol component to dibasic component is inthe range of 0.95110 to 1.0:1.l0.

2. A linear polyester according to claim 1 wherein R and R are methyl orethyl.

3. A linear polyester according to claim 2 wherein R' and R" are methyl.

4. A linear polyester according to claim 3 wherein R is cyclopentylene.

5. A linear polyester according to claim 3 wherein R is cyclohexylene.

6. A linear polyester according to claim 3 wherein R is bicyclo [4.4.0]decylene.

References Cited UNITED STATES PATENTS 3,342,880 9/ 1967 Reinhardt260648 3,467,627 9/1969 Duling et al. 26075 MELVIN GOLDSTEIN, PrimaryExaminer US. Cl. X.R.

26047 C, 75 H, 75 N, 75 S

